In this study, eight different types of imidazolium-based ionic liquids (ILs) were applied as new solvents in the extraction of flavonoids from grape skin, and compared to the conventional organic ...solvent extraction that was not reported earlier. The structure of anions, cations and concentration of ILs significantly affected extraction yields. The highest mass fractions of proanthocyanidins and anthocyanins were obtained with 2.5 mol/L of 1-butyl-3-methylimidazolium bromide C
mimBr and 2.5 mol/L of 1-ethyl-3-methylimidazolium bromide C
mimBr, respectively. The studied ILs provided an excellent preliminary result in the extraction of anthocyanins. Significantly higher mass fractions of total and all free anthocyanins were extracted with 2.5 mol/L of C
mimBr and 2.5 mol/L of 1-methylimidazolium hydrogen sulfate mimHSO
than with conventional solvent with the exception of anthocyanin-3-O-acetylmonoglucosides in the latter. On the other hand, 2.5 mol/L of C
mimBr and 2.5 mol/L of 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate sC
mimHSO
showed significantly higher selectivity towards anthocyanin-3-O-acetylmonoglucosides and anthocyanin-3-(6-O-
-coumaroyl)monoglucosides.
The main objective of this study was to compare chemical, rheological and sensory characteristics of kefir produced by using kefir grains and kefir starter. The intent was also to investigate whether ...it is plausible to use a combined inoculum (kefir grains and starter) in order to obtain a kefir with improved characteristics in terms of sensory and rheological characteristics. Kefir samples were produced at 25 °C and 35 °C by using starter culture XPL-1, kefir grains and their combinations. All of the produced kefir samples were analysed for acidity, total dry matter, ethanol content, syneresis, viscosity and were sensory evaluated by a specially trained panel. There were no significant differences considering the total dry matter, syneresis, ethanol content and acidity. Excess viscosity was observed in samples produced by starter culture at 35 °C, which was described as untypical, yoghurt like and unsatisfactory by a sensory panel. The sample produced at 25 °C by equal amounts of kefir grains and starter culture received the highest scores at sensory evaluation and showed the best potential for optimizing the further use. Further investigations need to focus on examining kefir properties during the storage period, especially regarding microbiological and sensory properties, ethanol content and texture profile.
•Different treatments during aging can impact outcomes of micro-oxygenation.•Intensity of phenolic changes depends on SO2, Fe with Cu and gelatin fining.•High concentrations of SO2 delay phenolic ...changes, impact color and astringency.•High levels of Fe and Cu can accelerate phenolic changes and affect color.•Gelatin fining reduces wine astringency and color intensity after long-term aging.
This work aimed to study long-term impact of micro-oxygenation and/or different aging treatments: (i) high SO2, (ii) high Fe with Cu and (iii) gelatin fining on Plavac mali red wine phenolic and in-mouthfeel sensory development in barrels and furthermore in bottles. Results showed that outcomes of micro-oxygenation strongly depend on aging treatments. High SO2 concentration during aging in barrels and bottles delayed typical phenolic changes and slightly contributed to astringency and lower color intensity, particularly in wine that was not micro-oxygenated. High metal concentrations and gelatin fining promoted intensive polymerization of proanthocyanins and a lower percentage of prodelphinidins after long-term aging in barrels. Also, flavan-3-ol and anthocyanins transformation rates in micro-oxygenated wines of both treatments significantly differed from their controls. Gelatin fining proved to be a very effective treatment for astringency reduction, particularly when combined with micro-oxygenation, but fined wines after long term aging in bottles showed lower color intensity.
In order to improve the quality of dehydrated fruit products, the influence of the addition of two sugars (sucrose and trehalose) on the retention of aroma components during dehydration of strawberry ...puree was investigated. Manual headspace solid-phase microextraction (SPME), containing polydimethylsiloxane coated fibre (100 μm) coupled with gas chromatography (GC-FID and GC-MS) was used for the analysis of the aroma of strawberry puree dehydrated by using freeze drying and foam-mat drying. The analytes identified included esters, carbonyl compounds, terpenoids, several alcohols and acids. The results obtained in this study give further insight into the mechanisms concerning the application of trehalose as flavouring additive, due to its ability to retain and preserve the fruit volatiles responsible for the characteristic flavour of fresh fruits during dehydration processes. The best retention of aroma components in dehydrated strawberry puree was obtained by trehalose addition when combined with freeze drying.
The aim of the research was characterization and improvement of aroma of white wine Vitis vinifera L. Pošip by application of several enological practices, either individually or in combinations. The ...effect of pre-fermentative maceration, indigenous yeast strain and antioxidant additions (higher sulfur dioxide and glutathione) was examined, and compared to conventional white wine production: reductive pressing, commercial yeast strain and typical doses of free sulfur dioxide (35 mg/L). The most significant aroma contributors were esters and higher alcohols (fermentation aroma), as well as varietal aroma compounds such as linalool, β-damascenone and thiols (3SH and 3SHA). Furthermore, results showed that pre-fermentative maceration affected the higher concentrations of several aroma compounds, primarily those important for varietal character of wines: terpenes, norisoprenoids and varietal thiols. Fermentation by indigenous yeasts resulted in higher concentrations of different compounds, especially of i-amyl acetate which contributes to desirable fruity, banana-like odors. Furthermore, during 12 months’ aging, most of the aroma compounds significantly decreased, but in wines bottled with antioxidant additions (higher free sulfur dioxide, glutathione and their combination) their slower decrease was observed. The most notable protective effect was observed using the combination of higher free sulfur dioxide (50 mg/L) with glutathione (20 mg/L).
•Positive correlation between pre-fermentation maceration and varietal aroma compounds.•Positive correlation between indigenous yeast strain and esters.•Signficant decrease in concentrations of aroma compounds during aging.•Combination of sulfur dioxide with glutathione has the most protective antioxidant effect.
The cold plasma is an emerging electrotechnology for the improvement of food safety without loss of physicochemical or sensory properties. The purpose of this study was to evaluate the effects of ...plasma treatments on the chromatic characteristics and phenolic composition of red and white wines. The red wine Cabernet Sauvignon and white wine Graševina were treated with high voltage electrical discharge plasma considering the variations in frequency (60, 90 and 120Hz) and processing time (3, 5 and 10min). Total phenolics, total anthocyanins, total tannins and chromatic characteristics were analyzed by spectrophotometry while free anthocyanins, phenolic acids and flavan-3-ols by the HPLC-UV/Vis. Obtained results illustrated that plasma treatments have influenced the stability of phenolic compounds in wines without major changes in color parameters. Also, among two different processing parameters, the duration time was the most significant factor inducing changes on wines.
High voltage electrical discharge plasma has been shown to affect the stability of wine phenols without any significant change in the color. An increase in the concentration of certain phenolic compounds in white wine suggest that this technique could be used in the wine industry as an alternative technique for enhancing the oxidative stability of wine and consequently the wine quality during the aging process.
•Plasma treatments have influenced the stability of wine phenols.•Plasma treatments did not affect significantly the wine color.•Plasma treatments increased the concentration of certain phenols in white wine.•Plasma treatment duration was more important factor in determining the wine quality.
The aim of this research was to investigate the short- and long-term effects of thermosonication and different physicochemical properties of wine on culturability, viability, and metabolic activity ...of
yeast. Thermosonication was conducted at 43 °C during 1, 2, and 3 min, while wine variations included several pH, alcohol, and sugar levels. Cell culturability and viability were determined immediately after treatment and during 90 days of storage, while metabolic activity was determined after 90 days of storage. Results showed that, although culturability was not confirmed in dry wines immediately after 3 min of treatment, thermosonication did not result in complete inactivation of the
population. Herein, the first evidence of a viable but not culturable (VBNC) state of
after thermosonication exposure was observed. Moreover, thermosonication reduced the production of volatile phenols. Obtained results suggest application of thermosonication for reduction of the
population only in early stages of wine contamination.
•The HPU treatment showed reduction in Brettanomyces yeast as well as in LAB.•Less than one minute of HPU treatment for the 90% reduction of Brettanomyces yeasts.•Slightly longer than one minute of ...ultrasound treatment for the 90% reduction of LAB.•Sensory testing of the HPU treated wine samples shows an impaired aroma of wine.
The purpose of this study was to investigate the effect of non-thermal technology, a high power ultrasound (HPU) in continuous flow treatment on the reduction in number of Brettanomyces yeasts and lactic acid bacteria (LAB) in wine samples. Yeast cells and lactic acid bacteria were screened for their sensitivity to a high power ultrasound treatment using an ultrasonic processor (400W, 24kHz, 100μm amplitude) at two different wine temperatures (30 and 40°C). High power ultrasound treatment in continuous flow showed satisfactory reduction of Brettanomyces yeasts (89.1–99.7%) and lactic acid bacteria (71.8–99.3%). Sensory properties of wine were impaired. The results indicate a great potential for the application of HPU in continuous flow system for wine processing in terms of lower usage of SO2 and preservatives. More attention is needed to preserve sensorial properties of wine.
PDF
